The CISC serves the enter's complex and multifaceted needs with respect to hardware, software, communications, monitoring data resources and routine descriptive analyses of data. Inferential statistics are performed under the purview of the Methodology and Statistics Core. Seven tasks are performed by this core: (1) managing the local area network; 2) managing the computing and information system (e.g. data codification, acquisition, scoring); 3) managing the control system; 4) monitoring subject and data flow to minimize subject attrition and missing data; 5) 5) consultation to CEDAR faculty regarding database design and management; 6) designing, managing and updating the Web page; and 7) updating the electronic database on drug abuse etiology under contract from NIDA. This latter effort will ultimately enable a fully interactive search and become part of NIDA's Homepage. As part of its routine analyses and reporting duties, the CISC conducts numerous analyses to explore the possibility of bias. Reported herein are results strongly indicating t that there is no indication for a sampling (recruitment) bias, subject attrition bias or missing data (implementation) bias.